I’ve recently suggested a wifi extended/repeater to a friend of mine as his wifi signals stuggles to reach his room. I’ve read about wifi repeaters and suggested one to my Friend. He bought one hearing my suggestion and fu*ked up.
The repeater caused huge jitter and latency and made the internet unusable. Luckily he doesn’t remember who suggested it🤷♂️
In my experience it works across circuits, but speeds aren’t that great. Just connect them to the same outlet first for pairing. I’ve heard about this method working between apartments too.